function rollLoading(id){
  var tag = "<div class='loading' />";
  document.getElementById(id).innerHTML = tag;
}
function limpiarDiv(id){
  document.getElementById(id).innerHTML = "";
}
function numbersonly(myfield, e, dec) {                                                                                   
  var key;                                                                                                           
  var keychar;                                                                    
  if (window.event)                                                                                                      
    key = window.event.keyCode;                                                                                                
  else if (e)                                                                                                                  
    key = e.which;                                                                                                             
  else                                                                                                                         
    return true;                                                                                                               
  keychar = String.fromCharCode(key);                                                                                          
                                                                                                                               
  // control keys                                                                                                              
  if ((key==null) || (key==0) || (key==8) ||                                                                                   
      (key==9) || (key==13) || (key==27) )                                                                                     
    return true;                                                                                                               
                                                                                                                               
  // numbers                                                                                                                   
  else if ((("0123456789").indexOf(keychar) > -1))                                                                             
    return true;                                                                                                               
                                                                                                                               
  // decimal point jump                                                                                                        
  else if (dec && (keychar == "."))                                                                                            
    {                                                                                                                          
    myfield.form.elements[dec].focus();                                                                                        
    return false;                                                                                                              
    }                                                                                                                          
 return false;                                                                                                            
}
